<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.com">
<head>
    <meta charset="UTF-8">

    <!-- css -->
    <link rel="stylesheet" th:href="@{/css/mycss.css}">
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet"
          crossorigin="anonymous">
    <!-- /css -->
    <title>Title</title>
</head>
<body>
<h1>这是一个test页面</h1>
</body>
</html>